1. Field
At least one embodiment of the present invention relates to an information communication system in which various presence information items such as existence or nonexistence information, attribute information and positional information of persons, things, equipments and the like is automatically notified from a central device to a granted terminal device.
2. Description of the Related Art
Owing to the spread of a communication infrastructure, the full-time connection of a communication device to a network has become possible.
Accordingly, there has been built an information communication system called a “presence system” wherein presence information regarding a person who uses a communication device connected to the network can be notified to other communication devices connected to the network. For example, a type of presence information describes availability of such a user (e.g., online, offline, away, etc.) and willingness of such a user to communicate via set of communication services.
In the presence system, in a case where the presence information indicating a present state of a subject object, e.g., a person, a thing, a piece of equipment or the like has been updated, a notification of such an update is notified in real time to a subscriber object which has made a request for an alteration notification vis-à-vis the presence information of the subject object and for which the request has been granted.
Here, the subject object which provides the presence information and which grants or rejects requests for alteration notification vis-à-vis its presence information is called a “presentity”. The subject object which has made the request for the alteration notification (and, if approved, receives the same) can be described as watching the presence information of the presentity, and so is called a “watcher”.
In addition, the watcher is described as having a “subscription to the presence information.” To become a watcher, the subscriber object subscribes, via submission of a subscription request, to presence information and alteration notifications regarding the presentity notified
In recent years, paths/schemes for transmitting and receiving information items through a network in real time have increased. By way of examples, there can be a case where information items are exchanged between persons, a case where information in a certain system is transmitted to another system, a case where information is transmitted to a system when a thing has been detected by utilizing an RFID (Radio Frequency IDentification) tag, etc.
It is expected to expand the applications of a presence system to multifarious systems by utilizing the point that information items can be transmitted and received in real time.
In a presence system according to the related art, in a case where a watcher subscribes to the presence of a presentity, an inquiry about the propriety of the presence subscription is made to the pertinent presentity. In this case, the presentity judges the propriety of the subscription inquiry from each watcher, and he/she responds to the inquiry about the subscription propriety. Where the presentity has granted the presence subscription, the presence information is notified to the watcher each time the presentity thereafter updates the presence information. In a case where the presentity has rejected the presence subscription, the presence information is not notified to the watcher even when the presentity has thereafter updated the presence information.
As stated above, in the presence system, the watchers make requests for the subscriptions to the presence information items of the presentities beforehand, and the presence information items are notified to only the watchers to whom the presentities have granted the subscriptions in compliance with the requests. On the other hand, in such a case where a communication device which the watcher uses is not operating, e.g., because it is not online, or where the watcher is absent, the pertinent watcher does not accept the presence information. In this case, the presence information is not reliably notified even when the content thereof is to be confirmed in real time. According to one related art method, when the watcher shifts into a state in which he/she does not accept the presence information, the notification destination to which it is desired for the presence information to be sent is altered to another proxy notification destination.
Japanese Patent Application Laid-Open No. 2006-209193 discloses a technique wherein, before the watcher falls into the state in which he/she does not accept the presence information, he/she selects the proxy notification destination to which it is desired that the presence information be sent and issues a notification destination alteration request. Accordingly, having accepted the notification destination alteration request, the presence system decides the propriety of this notification destination alteration request on the basis of an alteration propriety condition set beforehand. In this case, the notification destination to which it is desired that the presence information be sent is altered when the presence system has decided the alteration to be proper, in compliance with the notification destination alteration request.
With this technique, the watcher can designate an alteration time period in issuing the notification destination alteration request. In this regard, there is disclosed a technique wherein, when the alteration time period has lapsed after the issue of the notification destination alteration request, the notification destination is reverted to the original watcher.
With the above technique, however, each time the watcher shifts into the state in which he/she does not accept the presence information, he/she needs to designate the next proxy notification destination and to notify the alteration request by himself/herself. This technique is relatively labor-intensive, and thus troublesome, for the watcher.
Besides, Non-patent Document 1 (Fujitsu Kabushiki-Kaisha: “Start of Sale of Software which realizes Push-type Information Delivery corresponding to Situation of User ‘FLAIRINC (registered trademark)’”, [online], dated Dec. 2, 2002 [searched for on Oct. 2, 2007] discloses a technique wherein, in a case where the watcher is in the state in which he/she does not accept the presence information, the presence information is transferred to a mail address designated by the watcher.
In this case, before the watcher falls into the state in which he/she does not accept the presence information, he/she designates the mail address so as to transfer the presence information to another communication device of his/her own or another watcher. Thus, even in the state in which the watcher does not accept the presence information, the presence information is notified to any watcher.